An attacker obtains an authoritative or reputable signer's private signature key by exploiting a cryptographic weakness in the signature algorithm or pseudorandom number generation and then uses this key to forge signatures from the original signer to mislead a victim into performing actions that benefit the attacker.

Multiple checksum validation flaws were discovered in the MIT Kerberos implementation. A remote attacker could use these flaws to tamper with certain Kerberos protocol packets and, possibly, bypass authentication mechanisms in certain configurations using Single-use Authentication Mechanisms. (CVE-2010-1323)
After installing the updated packages, the krb5kdc daemon will be restarted automatically.

The remote host is affected by the vulnerability described in GLSA-201201-13 (MIT Kerberos 5: Multiple vulnerabilities)
Multiple vulnerabilities have been discovered in MIT Kerberos 5. Please review the CVE identifiers referenced below for details.
Impact :
A remote attacker may be able to execute arbitrary code with the privileges of the administration daemon or the Key Distribution Center (KDC) daemon, cause a Denial of Service condition, or possibly obtain sensitive information. Furthermore, a remote attacker may be able to spoof Kerberos authorization, modify KDC responses, forge user data messages, forge tokens, forge signatures, impersonate a client, modify user-visible prompt text, or have other unspecified impact.
Workaround :
There is no known workaround at this time.

a. ESX/ESXi Socket Exhaustion By sending malicious network traffic to an ESXi or ESX host an attacker could exhaust the available sockets which would prevent further connections to the host. In the event a host becomes inaccessible its virtual machines will continue to run and have network connectivity but a reboot of the ESXi or ESX host may be required in order to be able to connect to the host again.
ESXi and ESX hosts may intermittently lose connectivity caused by applications that do not correctly close sockets. If this occurs an error message similar to the following may be written to the vpxa log :
socket() returns -1 (Cannot allocate memory)
An error message similar to the following may be written to the vmkernel logs :
socreate(type=2, proto=17) failed with error 55
VMware would like to thank Jimmy Scott at inet-solutions.be for reporting this issue to us.
The Common Vulnerabilities and Exposures Project (cve.mitre.org) has assigned the name CVE-2011-1785 to this issue.
b. Likewise package update Updates to the vmware-esx-likewise-openldap and vmware-esx-likewise-krb5 packages address several security issues.
One of the vulnerabilities is specific to Likewise while the other vulnerabilities are present in the MIT version of krb5.
An incorrect assert() call in Likewise may lead to a termination of the Likewise-open lsassd service if a username with an illegal byte sequence is entered for user authentication when logging in to the Active Directory domain of the ESXi/ESX host. This would lead to a denial of service.
The MIT-krb5 vulnerabilities are detailed in MITKRB5-SA-2010-007.
The Common Vulnerabilities and Exposures project (cve.mitre.org) has assigned the names CVE-2011-1786 (Likewise-only issue), CVE-2010-1324, CVE-2010-1323, CVE-2010-4020, CVE-2010-4021 to these issues.
c. ESX third-party update for Service Console kernel The Service Console kernel is updated to include a fix for a security issue.
The Common Vulnerabilities and Exposures project (cve.mitre.org) has assigned the name CVE-2010-2240 to this issue.

s700_800 11.31 KRB5-Client Version 1.3.5.03 Cumulative patch :
Potential security vulnerabilities have been identified on HP-UX running Kerberos. These vulnerabilities could be exploited remotely by an unauthorized user to modify data, prompts, or responses.

The remote VMware ESX / ESXi host is missing a security-related patch.
It is, therefore, affected by multiple vulnerabilities :
- Multiple forgery vulnerabilities exist in the bundled version of MIT Kerberos 5 (krb5). An attacker can exploit these issues to impersonate a client, escalate privileges, and disclose sensitive information.
(CVE-2010-1323, CVE-2010-1324, CVE-2010-4020, CVE-2010-4021)
- A local arbitrary code execution vulnerability exists in the Kernel in the do_anonymous_page() function due to improper separation of the stack and the heap. A local attacker can exploit this vulnerability to execute arbitrary code. (CVE-2010-2240)
- A denial of service vulnerability exists that allows a remote attacker to exhaust available sockets, preventing further connections. (CVE-2011-1785)
- A denial of service vulnerability exists in the bundled version of lsassd in Likewise Open. A remote attacker can exploit this, via an Active Directory login attempt that provides a username containing an invalid byte sequence, to cause a daemon crash. (CVE-2011-1786)

A vulnerability has been found in krb5, the MIT implementation of Kerberos.
MIT krb5 clients incorrectly accept unkeyed checksums in the SAM-2 preauthentication challenge: an unauthenticated remote attacker could alter a SAM-2 challenge, affecting the prompt text seen by the user or the kind of response sent to the KDC. Under some circumstances, this can negate the incremental security benefit of using a single-use authentication mechanism token.
MIT krb5 incorrectly accepts RFC 3961 key-derivation checksums using RC4 keys when verifying KRB-SAFE messages: an unauthenticated remote attacker has a 1/256 chance of forging KRB-SAFE messages in an application protocol if the targeted pre-existing session uses an RC4 session key. Few application protocols use KRB-SAFE messages.
The Common Vulnerabilities and Exposures project has assigned CVE-2010-1323 to these issues.

This update incorporates the upstream patches to correct bugs outlined in MITKRB5-SA-2010-007 (CVE-2010-1323, CVE-2010-1324, and CVE-2010-4020).
Note that Tenable Network Security has extracted the preceding description block directly from the Fedora security advisory. Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues.

Updated krb5 packages that fix multiple security issues and one bug are now available for Red Hat Enterprise Linux 6.
The Red Hat Security Response Team has rated this update as having important security impact. Common Vulnerability Scoring System (CVSS) base scores, which give detailed severity ratings, are available for each vulnerability from the CVE links in the References section.
Kerberos is a network authentication system which allows clients and servers to authenticate to each other using symmetric encryption and a trusted third party, the Key Distribution Center (KDC).
Multiple checksum validation flaws were discovered in the MIT Kerberos implementation. A remote attacker could use these flaws to tamper with certain Kerberos protocol packets and, possibly, bypass authentication or authorization mechanisms and escalate their privileges.
(CVE-2010-1323, CVE-2010-1324, CVE-2010-4020)
Red Hat would like to thank the MIT Kerberos Team for reporting these issues.
This update also fixes the following bug :
* When attempting to perform PKINIT pre-authentication, if the client had more than one possible candidate certificate the client could fail to select the certificate and key to use. This usually occurred if certificate selection was configured to use the value of the keyUsage extension, or if any of the candidate certificates did not contain a subjectAltName extension. Consequently, the client attempted to perform pre-authentication using a different (usually password-based) mechanism. (BZ#644825)
All krb5 users should upgrade to these updated packages, which contain backported patches to correct these issues. After installing the updated packages, the krb5kdc daemon will be restarted automatically.

The remote OracleVM system is missing necessary patches to address critical security updates :
- Fix for (CVE-2011-4862)
- incorporate a fix to teach the file labeling bits about when replay caches are expunged (#712453)
- rebuild
- ftp: handle larger command inputs (#665833)
- don't bail halfway through an unlock operation when the result will be discarded and the end-result not cleaned up (Martin Osvald, #586032)
- add a versioned dependency between krb5-server-ldap and krb5-libs (internal tooling)
- don't discard the error code from an error message received in response to a change-password request (#658871, RT#6893)
- ftpd: add patch from Jatin Nansi to correctly match restrict lines in /etc/ftpusers (#644215, RT#6889)
- ftp: add modified patch from Rogan Kyuseok Lee to report the number of bytes transferred correctly when transferring large files on 32-bit systems (#648404)
- backport fix for RT#6514: memory leak freeing rcache type none (#678205)
- add upstream patch to fix hang or crash in the KDC when using the LDAP kdb backend (CVE-2011-0281, CVE-2011-0282, #671097)
- incorporate upstream patch for checksum acceptance issues from MITKRB5-SA-2010-007 (CVE-2010-1323, #652308)
- backport a fix to the previous change (#539423)
- backport the k5login_directory and k5login_authoritative settings (#539423)
- krshd: don't limit user names to 16 chars when utmp can handle names at least a bit longer than that (#611713)
- fix a logic bug in computing key expiration times (RT#6762, #627038)
- correct the post-rotate scriptlet in the kadmind logrotate config (more of #462658)
- ftpd: backport changes to modify behavior to match telnetd,rshd,rlogind and accept GSSAPI auth to any service for which we have a matching key (#538075)
- pull in fix for RT#5551 to treat the referral realm when seen in a ticket as though it were the local realm (#498554, also very likely #450122)
- add aes256-cts:normal and aes128-cts:normal to the list of keysalts in the default kdc.conf (part of #565941)
- add a note to kdc.conf(5) pointing to the admin guide for the list of recognized key and salt types (the rest of #565941)
- add logrotate configuration files for krb5kdc and kadmind (#462658)
- libgssapi: backport patch from svn to stop returning context-expired errors when the ticket which was used to set up the context expires (#605367, upstream #6739)
- enable building the -server-ldap subpackage (#514362)
- stop caring about the endianness of stash files (#514741), which will be replaced by proper keytab files in later releases
- don't crash in krb5_get_init_creds_password if the passed-in options struct is NULL and the clients keys have expired (#555875)
- ksu: perform PAM account and session management before dropping privileges to those of the target user (#540769 and #596887, respectively)
- add candidate patch to correct libgssapi null pointer dereference which could be triggered by malformed client requests (CVE-2010-1321, #583704)
- fix a null pointer dereference and crash introduced in our PAM patch that would happen if ftpd was given the name of a user who wasnt known to the local system, limited to being triggerable by gssapi-authenticated clients by the default xinetd config (Olivier Fourdan, #569472)
- add upstream patch to fix a few use-after-free bugs, including one in kadmind (CVE-2010-0629, #578186)
- merge patch to correct KDC integer overflows which could be triggered by malformed RC4 and AES ciphertexts (CVE-2009-4212, #546348)
- pull changes to libkrb5 to properly handle and chase off-path referrals back from 1.7 (#546538)
- add an auth stack to ksus PAM configuration so that it can successfully pam_setcred
- also set PAM_RUSER in ksu for completeness (#479071+#477033)
- fix various typos, except for bits pertaining to licensing (#499190)
- kdb5_util: when renaming a database, if the new names associated lock files don't exist, go ahead and create them (#442879)
- ksu: perform PAM account and session management for the target user authentication is still performed as before (#477033)
- fix typo in ksus reporting of errors getting credentials (#462890)
- kadmind.init: stop setting up a keytab, as kadminds been able to use the database directly for a while now (#473151)
- pull up patch to set PAM_RHOST (James Leddy, #479071)

The MIT Kerberos team reports :
MIT krb5 clients incorrectly accept an unkeyed checksums in the SAM-2 preauthentication challenge.
An unauthenticated remote attacker could alter a SAM-2 challenge, affecting the prompt text seen by the user or the kind of response sent to the KDC. Under some circumstances, this can negate the incremental security benefit of using a single-use authentication mechanism token.
MIT krb5 incorrectly accepts RFC 3961 key-derivation checksums using RC4 keys when verifying KRB-SAFE messages.
An unauthenticated remote attacker has a 1/256 chance of forging KRB-SAFE messages in an application protocol if the targeted pre-existing session uses an RC4 session key. Few application protocols use KRB-SAFE messages.

Multiple remote vulnerabilities in the MIT krb5 package have been fixed. They affect client as well as server software. CVE-2010-1323, CVE-2010-1324,CVE-2010-4020 and CVE-2010-4021 have been assigned to this issue.

A vulnerability was discovered and corrected in krb5 :
An unauthenticated remote attacker could alter a SAM-2 challenge, affecting the prompt text seen by the user or the kind of response sent to the KDC. Under some circumstances, this can negate the incremental security benefit of using a single-use authentication mechanism token. An unauthenticated remote attacker has a 1/256 chance of forging KRB-SAFE messages in an application protocol if the targeted pre-existing session uses an RC4 session key. Few application protocols use KRB-SAFE messages (CVE-2010-1323).
Packages for 2009.0 are provided as of the Extended Maintenance Program. Please visit this link to learn more:
http://store.mandriva.com/product_info.php?cPath=149&products_id=4 90
The updated packages have been patched to correct this issue.

Multiple vulnerabilities were discovered and corrected in krb5 :
An unauthenticated remote attacker could alter a SAM-2 challenge, affecting the prompt text seen by the user or the kind of response sent to the KDC. Under some circumstances, this can negate the incremental security benefit of using a single-use authentication mechanism token. An unauthenticated remote attacker has a 1/256 chance of forging KRB-SAFE messages in an application protocol if the targeted pre-existing session uses an RC4 session key. Few application protocols use KRB-SAFE messages (CVE-2010-1323).
An unauthenticated remote attacker can forge GSS tokens that are intended to be integrity-protected but unencrypted, if the targeted pre-existing application session uses a DES session key. An authenticated remote attacker can forge PACs if using a KDC that does not filter client-provided PAC data. This can result in privilege escalation against a service that relies on PAC contents to make authorization decisions. An unauthenticated remote attacker has a 1/256 chance of swapping a client-issued KrbFastReq into a different KDC-REQ, if the armor key is RC4. The consequences are believed to be minor (CVE-2010-1324).
An authenticated remote attacker that controls a legitimate service principal has a 1/256 chance of forging the AD-SIGNEDPATH signature if the TGT key is RC4, allowing it to use self-generated evidence tickets for S4U2Proxy, instead of tickets obtained from the user or with S4U2Self. Configurations using RC4 for the TGT key are believed to be rare. An authenticated remote attacker has a 1/256 chance of forging AD-KDC-ISSUED signatures on authdata elements in tickets having an RC4 service key, resulting in privilege escalation against a service that relies on these signatures. There are no known uses of the KDC-ISSUED authdata container at this time (CVE-2010-4020.
An authenticated remote attacker that controls a legitimate service principal could obtain a valid service ticket to itself containing valid KDC-generated authorization data for a client whose TGS-REQ it has intercepted. The attacker could then use this ticket for S4U2Proxy to impersonate the targeted client even if the client never authenticated to the subverted service. The vulnerable configuration is believed to be rare (CVE-2010-4021).
The updated packages have been patched to correct this issue.

Multiple remote vulnerabilities in the MIT krb5 package have been fixed. They affect client as well as server software. CVE-2010-1323, CVE-2010-1324,CVE-2010-4020 and CVE-2010-4021 have been assigned to this issue.

Multiple remote vulnerabilities in the MIT krb5 package have been fixed. They affect client as well as server software. CVE-2010-1323, CVE-2010-1324,CVE-2010-4020 and CVE-2010-4021 have been assigned to this issue.

Updated krb5 packages that fix multiple security issues are now available for Red Hat Enterprise Linux 4 and 5.
The Red Hat Security Response Team has rated this update as having moderate security impact. A Common Vulnerability Scoring System (CVSS) base score, which gives a detailed severity rating, is available from the CVE link in the References section.
Kerberos is a network authentication system which allows clients and servers to authenticate to each other using symmetric encryption and a trusted third party, the Key Distribution Center (KDC).
Multiple checksum validation flaws were discovered in the MIT Kerberos implementation. A remote attacker could use these flaws to tamper with certain Kerberos protocol packets and, possibly, bypass authentication mechanisms in certain configurations using Single-use Authentication Mechanisms. (CVE-2010-1323)
Red Hat would like to thank the MIT Kerberos Team for reporting these issues.
All krb5 users should upgrade to these updated packages, which contain a backported patch to correct these issues. After installing the updated packages, the krb5kdc daemon will be restarted automatically.

Updated krb5 packages that fix multiple security issues are now available for Red Hat Enterprise Linux 4 and 5.
The Red Hat Security Response Team has rated this update as having moderate security impact. A Common Vulnerability Scoring System (CVSS) base score, which gives a detailed severity rating, is available from the CVE link in the References section.
Kerberos is a network authentication system which allows clients and servers to authenticate to each other using symmetric encryption and a trusted third party, the Key Distribution Center (KDC).
Multiple checksum validation flaws were discovered in the MIT Kerberos implementation. A remote attacker could use these flaws to tamper with certain Kerberos protocol packets and, possibly, bypass authentication mechanisms in certain configurations using Single-use Authentication Mechanisms. (CVE-2010-1323)
Red Hat would like to thank the MIT Kerberos Team for reporting these issues.
All krb5 users should upgrade to these updated packages, which contain a backported patch to correct these issues. After installing the updated packages, the krb5kdc daemon will be restarted automatically.

From Red Hat Security Advisory 2010:0926 :
Updated krb5 packages that fix multiple security issues are now available for Red Hat Enterprise Linux 4 and 5.
The Red Hat Security Response Team has rated this update as having moderate security impact. A Common Vulnerability Scoring System (CVSS) base score, which gives a detailed severity rating, is available from the CVE link in the References section.
Kerberos is a network authentication system which allows clients and servers to authenticate to each other using symmetric encryption and a trusted third party, the Key Distribution Center (KDC).
Multiple checksum validation flaws were discovered in the MIT Kerberos implementation. A remote attacker could use these flaws to tamper with certain Kerberos protocol packets and, possibly, bypass authentication mechanisms in certain configurations using Single-use Authentication Mechanisms. (CVE-2010-1323)
Red Hat would like to thank the MIT Kerberos Team for reporting these issues.
All krb5 users should upgrade to these updated packages, which contain a backported patch to correct these issues. After installing the updated packages, the krb5kdc daemon will be restarted automatically.

It was discovered that Kerberos did not properly determine the acceptability of certain checksums. A remote attacker could use certain checksums to alter the prompt message, modify a response to a Key Distribution Center (KDC) or forge a KRB-SAFE message.
(CVE-2010-1323)
It was discovered that Kerberos did not properly determine the acceptability of certain checksums. A remote attacker could use certain checksums to forge GSS tokens or gain privileges. This issue only affected Ubuntu 9.10, 10.04 LTS and 10.10. (CVE-2010-1324)
It was discovered that Kerberos did not reject RC4 key-derivation checksums. An authenticated remote user could use this issue to forge AD-SIGNEDPATH or AD-KDC-ISSUED signatures and possibly gain privileges. This issue only affected Ubuntu 10.04 LTS and 10.10.
(CVE-2010-4020)
It was discovered that Kerberos did not properly restrict the use of TGT credentials for armoring TGS requests. A remote authenticated user could use this flaw to impersonate a client. This issue only affected Ubuntu 9.10. (CVE-2010-4021).
Note that Tenable Network Security has extracted the preceding description block directly from the Ubuntu security advisory. Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues.

This update incorporates the upstream patches to correct bugs outlined in MITKRB5-SA-2010-007 (CVE-2010-1323, CVE-2010-1324, and CVE-2010-4020).
Note that Tenable Network Security has extracted the preceding description block directly from the Fedora security advisory. Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues.